1. Field of the Invention
The field to which this invention applies is image correlation, in particular, correlation using only data that represents spatial parameters. A specific application is correlation of digitally processed data obtained from a scanning laser such as a LADAR.
2. Background
It is known to use multispectral image correlation systems in air-to-ground target detection and acquisition. Such systems include means for image-processing, which automatically register images produced by airborne platform-mounted sensors operating in different wavelengths and from different points of view.
It is further known that an effective technique for registering images from different sensor types is that of edge matching, that is, matching pronounced target scene edges appearing in one sensor image with similar target scene edges appearing in one or more other sensor images. However, conventional image processing techniques for edge extraction rely upon detection of discontinuities in the light intensity of adjacent pixels, which often produces unsatisfactory results because of reflected laser energy which exhibits large random fluctuations from pixel to pixel, because of atmospheric effects, surface texture, and receiver noise. Such random fluctuations can overwhelm systematic variations caused by the reflectance of the target.
Accordingly, there is a need for a method and system for target detection acquisition, and terminal guidance, utilizing edge extraction from laser-radar (ladar) images relying solely on spatial information, rather than light intensity data.